Optical and microstructural characterization of chemically synthesized gallium nitride nanopowders

Thermal decomposition of an amido precursor; [Ga-2(NMe2)(6), Me=CH3] in an ammonia atmosphere yielded nanostructured gallium nitride powder. The x-ray diffraction spectrum of the nanosized gallium nitride exhibited reflections corresponding to the lattice planes of fee (zinc blende) GaN. High resolution transmission electron microscopy confirmed the cubic structure of the material and evidence of stacking faults within the fee structure. Infrared spectra showed the characteristic Ga-N stretch at 550 cm(-1). Transmission electron microscope measurements indicated that the GaN consisted of approximate to 50 nm sized particles which in turn are agglomerates of smaller particles with approximate to 5 nm domain sizes. The photoluminescence (PL) emission spectrum of the GaN was found to be sensitive to the excitation wavelength exhibiting peaks at 378 and 317 nm. The PL excitation spectrum showed resonances in the 200-300 nm region. These PL results suggest the effect of quantum confinement in these GaN particles. (C) 1997 American Institute of Physics.